The invention relates to a bumper for an automotive vehicle, including a bending-resistant support resting on parts affixed to the vehicle, an undulating leaf spring extending over the length of the bumper arranged in front of this support, and a cover which locks onto the support for covering the leaf spring from view.
Such a bumper is known from DOS [German Unexamined Laid-Open Application] No. 2,418,459 wherein the spring, capable of energy absorption, consists of a metallic material and is introduced as a separate component into a cavity between a support and a cover. The undulations of the leaf spring are supported, in their turning zones, alternatingly against the support and the cover, so that no supporting is effected between two turning zones. For this reason, with a spotwise contact of the cover outside of the supporting zones, there is the danger of a local overextension of the cover so that the latter must be replaced even in case of a relatively harmless collision.
It is an object of the invention to ensure, while reducing the number of individual parts and the assembly expenses, that spotwise effects of an impact do not lead to permanent deformation effects on the cover.
For this reason, a bumper is proposed of the type discussed hereinabove wherein, according to this invention, the leaf spring is joined integrally with the support, which latter consists preferably of a reinforced synthetic resin, and wherein the undulating windings of the leaf spring are aligned, in the zone of the support extending at right angles to the vehicle, in the longitudinal vehicle direction and, in laterally wrapped-around end zones of the support, approximately in the transverse vehicle direction.
In one embodiment of the invention, the support includes at least two sections extending over the length of the bumper, these sections being connected to each other by mounting elements arranged along the route of the superimposed windings. In case of stress, a relative movement takes place between the superimposed windings, with energy absorption.
To further increase energy absorption, it is proposed to provide that the windings, in their open region in opposition to the respectively associated turning zone thereof, are supported by way of energy-absorbing elements against each other and/or against the support.
In especially preferred embodiments of the invention, the energy-absorbing elements consists of a foam material.
Overstressing of the leaf spring can be avoided by providing, instead of or additionally to the energy-absorbing elements, impact buffers limiting the inward stroke movements of the windings, according to certain preferred embodiments. These impact buffers are considered in cases where the amount of blockage occurring upon exhaustion of the energy-absorbing power of the energy-absorbing elements is too small.
According to certain preferred embodiments, at least one turning zone of the windings can be provided with cutouts in order to adapt the spring characteristic.
An elasticity modulus adapted to requirements can be advantageously attained, according to preferred embodiments, by providing that the reinforcements in the support consist of fibers oriented primarily--in adaptation to the profile configuration of the support--in the direction of a vertical vehicle axis and of a longitudinal vehicle axis, and by providing that also the leaf spring is reinforced by fibers oriented predominantly in the transverse direction of the vehicle.
Finally, it is also contemplated to adapt the wall thickness and/or the fiber density of the support to the loads which may be encountered.
Further objects, features, and advantages of the present invention will become more obvious from the following description when taken in connection with the accompanying drawings which show, for purposes of illustration only, several embodiments in accordance with the present invention.